Cell and Tissue Journal

Abstract Introduction: Concerns about fossil energy costs, environmental deterioration, and energy security has created strong motivation for the research and development of routes to provide sustainable and renewable fuels. In recent years, the use of biomass to produce highly valued chemicals has attracted widespread attention. Lignocellulosic biomass, as a promising renewable resource for biofuel production, has distinct advantages in terms of economic and environmental benefits. The conversion of renewable raw materials to hydrocarbon fuels is an attractive alternative to fossil fuels from economic and environmental perspectives. The production process of lignocellulosic biomass mainly consists of biomass accumulation, biomass decomposition, simple sugars, and conversion of sugars to biofuel. One of the crucial steps for the economic success of lignocellulosic biofuels depends on the inhibition of competitive metabolism in microorganisms to achieve high productivity. To date, there has been a growing focus on the use of S. cerevisiae and E. coli as cell lines. These two cellular factories have well known advantages. They are genetically transmissible and several tools are available for genetic manipulation. In order to produce xylonate, the engineered xylose is first converted by a dehydrogenase into the intermediate xylonolactone, which is then slowly converted to xylonate in a nonenzymatic reaction.
Aim: The organic compound D-1,2,4-Butanetriol (BT) is a valuable chemical with wide-ranging applications in various fields such as pharmaceuticals, paper, polymer materials, and military applications. However, the chemical synthesis routes for BT have many drawbacks. By genetically modifying microorganisms, the metabolic pathway for producing many substances, including BT, can be engineered. When D-xylose is supplied to the bacterium, it is first converted into an intermediate compound called xylonolactone. This compound slowly converts into xylonate through a non-enzymatic reaction. To produce xylonate, the engineered bacteria receive xylose, which is initially converted by a dehydrogenase reaction catalysed by the xylose dehydrogenase enzyme into an intermediate compound, xylonolactone. Xylonolactone is slowly converted to xylonate in a nonenzymatic reaction. Xylonate is a five-carbon organic acid. Over the past few years, xylonate has increasingly been considered as an important chemical due to its potential as an important chemical component. Xylonate has many applications in the food, chemical, and pharmaceutical industries. Specifically, xylonate can act as a precursor for the synthesis of D-1,2,4-Butanetriol and as a concrete water reducing agent. E. coli was chosen as the target strain for genetic and metabolic engineering due to its fast growth in inexpensive culture media, the presence of two enzymes for BT synthesis, and product formation in less than 24 hours of fermentation. This study aimed to clone and express xylose dehydrogenase from Caulobacter vibrioides in E.coli.
Materials and Methods: At first, to access the bacterial gene sequence, the genome of the target bacterium was extracted. Then, to create a strain expressing the enzymes xylose dehydrogenase and xylonolactonase, the genes for these proteins were amplified from Caulobacter vibrioides CB1 and transferred into E. coli. For this purpose, the target genes were amplified using specifically designed primers via the Polymerase Chain Reaction (PCR) method and initially cloned into a pTZ57cloning vector and then subcloned into pET 26b expression vector. At the final step, the expression of the enzyme was assessed by SDS-PAGE, and the other confirmation was the reduction of NAD+ to NADH, which was used as an activity indicator of the enzyme, as investigated by a change in NADH absorbance at 340 nm.
Results: Confirmatory tests were performed to ensure the presence of the gene in the vectors (using restriction enzymes and colony PCR for gene amplification). The expression and activity of the enzyme were analyzed. The recombinant protein's presence was confirmed by SDS-PAGE for the xylose dehydrogenase gene, with a molecular weight of 52.2 kDa. The estimated expression level of the recombinant protein was approximately 25%.
Conclusion: The objective of this research was solely to establish the metabolic pathway for xylonate production in E. coli by surface expression of enzymes in this pathway (xylose dehydrogenase). The results obtained in this study confirm that half of the pathway is active at the cell surface, but further experiments are required to determine the precise production levels and complete the pathway.

Abstract

Abstract Aim: In this study, the toxicity effect of silver nanoparticles on colon cancer (HT29) was measured and evaluate the expression of the matrix metalloproteinase 9 (MMP9) genes.
Material and methods: In this study, the synthesized AgNPs were characterized by the transmission electron microscopy (TEM) analysis. The cytotoxicity effect of silver nanoparticles against the HT29 cell lines was investigated using MTT assay. Also, MMP9 gene expression was measured using real time PCR technique.
Results: The TEM result showed that the fabricated AgNPs were mostly spherical in shape and having an average diameter of 22 nm. The results revealed that AgNPs significantly decreased the viability of cells in dose-and time dependent manner (p < 0.001). Also, there was a significant relationship between the differences in concentrations. MMP9 gene expression levels in HT29 cells were decreased to 0.4897 ± 0.00679 (p < 0.001) compared with the control group.
Conclusion: According to the results, the green fabricated AgNPs can be considered as a promising strategy for the treatment of colon cancer.
 

Abstract Aim: In this research, a simple and rapid method (green synthesis) was applied for synthesis of silver nanoparticles (AgNPs) using Scrophularia striata fruit extract, so that the metabolites present in S.striata fruit extract caused to reduce silver ions to AgNPs in green synthesis process.
Material and Methods: UV–visible spectroscopy and scanning electron microscopy (SEM) were used to characterize the synthesized nanoparticles from S. striata extract. The antibacterial activity of the synthesized silver nanoparticles from S. striata extract was investigated against Gram-negative bacteria (Escherichia coli clinical, Escherichia coli ATCC, Salmonella typhi ATCC and Klebsiella pneumoniae) and Gram-positive bacteria (Staphylococcus aureus and Bacillus cereus). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined using microdilution technique. The antibacterial activity was determined by agar well diffusion method.
Results: The results showed that with increased concentration of silver nanoparticles, antibacterial activity increased and in the concentration of 5 mM silver nanoparticles, antibacterial activity was observed against all bacteria, however the highest antibacterial activity of silver nanoparticles observed against Staphylococcus aureus (inhibition zone diameter with 32 mm). Also, in the low concentrations of 0.312 and 0.625 mM of silver nanoparticles, no inhibitory effects were observed on the Klebsiella pneumoniae and Salmonella typhi ATCC.
Conclusion: From the results, it is suggested that silver nanoparticles synthesized using S. striata fruit extract could be used as a suitable antibacterial agent against clinical pathogens.
 

Abstract Aim: In the present study, to compare the toxicity and possible oxidative stress that may result from application of silver nanoparticles and silver ions, the impacts of their different concentrations on some biochemical indices related to protein oxidation in potato (Solanum tuberosum) were investigated.
 Material and methods: potato explants with one node were transferred to MS medium containing 0, 2, 10 and 20 mg.L^-1silver nanoparticles (AgNPs) and silver nitrate (AgNO₃). After four weeks of exposure, in vitro-grown explants were harvested for measurement of various parameters.
Results: Total protein content in explants treated with either AgNPs or Ag ions decreased with increase in silver concentration, except in Ag ion treatment at 2 mg.L^-1, which it increased significantly as compared to control samples. Also, remarkable changes were observed in five bands of protein electrophoresis patterns. The contents of Carbonyl groups were significantly increased relative to control in a dose-dependent manner. In both silver treatments, protein thiols were significantly decreased, while non-protein thiols were amplified. Moreover, explants treated with Ag ions showed higher protease activity and total antioxidant power as compared to AgNPs treated ones.
Conclusion: Based on the results, it could be concluded that oxidative damage to explants treated with AgNPs was much more than explants under a similar mass of Ag ions. In addition to the release of silver ions, special effects associated with nanoparticles could be involved in the oxidative stress induced by AgNPs in potato explants.

Abstract Aim: In this study, the effects of curcumin- coated silver nanoparticles were examined on induction of apoptosis in ovarian cancer A2780 cell.
Material and Methods: Silver nanoparticles coated with curcumin were biosynthesized, then A2780 cells were treated with different concentration of silver nanoparticles. Cytotoxicity effects of silver nanoparticles in A2780 cells were assessed by MTT assay and apoptotic effects of these nanoparticles were examined using DAPI and acridine orange/ propidium iodide staining and caspase 3/9 activation assay. Changes in Bax and Bcl-2 gene expression were analyzed by Real Time PCR.
Results: Findings showed that silver nanoparticles inhibit A2780 cells proliferation in a dose dependent manner. 8 µg/ml 50% decreased cell viability at 24 hours, DAPI and, acridine orange propidium iodide staining represent that percentage of apoptotic cells in the treated groups was increased. The results of Real Time PCR showed that Bax gene expression in cells treated with silver nanoparticles increased, while Bcl-2 gene expression in the treated cells was decreased.
Conclusion: Silver nanoparticles coated with curcumin induce apoptosis in A2780 cancer cells. The use of the nanoparticles should be considered a promising strategy for the treatment of ovarian cancer.

Abstract Aim: The aim of this study was to evaluate the negative effects of different doses of silvernanoparticles on fertility potential, chromatin structureand DNA integrity of epididymal sperm in mice.
Material and Methods: Twenty four male mice were divided into 4 groups (n=6) including one control and three experimental groups for orally administration of silver nanoparticles with three different doses (50, 100 and 200 μl/kg/day) for 5 weeks. Then, cauda epididymal spermatozoa were aspirated for analysis of sperm parameters using general microscopy methods and according to WHO criteria. Chromatin condensation, intensity of sperm chromatin abnormalities and protamine deficiency were assessed by three different cytochemical tests including aniline blue (AB), toluidine blue (TB) and chromomycin A3 (CMA3) tests respectively.
Results: Results showed that third group (treated with the highest silvernanoparticles dose), had the lowest sperm number, the lowest of sperm fast motility percentage and the lowest sperm percentage having normal morphology significantly in comparison with control and others groups. The II and III groups significantly showed differences in sperm chromatin condensation and deficiency comparing to other groups.
Conclusion: In this study the negative effect of silver nanoparticles on mice sperm parameters, sperm chromatin structure and DNA integrity were observed. It is believed that the negative effects of silver nanoparticles on sperm quality are significant and depend on used doses.
 

Abstract Aim: Due to the role of silver nanoparticles on elevation of reactive oxygen species, and high sensitivity of spermatozoa to these agents, it is possible that silver nanoparticles reduce the fertility potential of spermatozoa. The aim of present study was to evaluate the effects of silver nanoparticles on sperm parameters and the concentration of reactive oxygen species in mouse serum and seminal fluid.
Material and Methods: In this experimental study, 24 adult male Syrian mice were divided into a control and three experimental groups. The experimental groups received silver nanoparticles orally at different doses (0.05, 0.1 and 0.2 ml orally) for 5 weeks. Then blood samples were taken from hearts to examine the Malondialdehyde (MDA) concentration by spectrophotometry. In addition, to analyze the sperm parameter cauda epididymis was dissected and swim-out spermatozoa were analyzed.
Results: The 3rd experimental group (highest dose) significantly showed the lowest mean of sperm count (16±2.6), the lowest percentage of rapid progressive motile spermatozoa (18.16±5.45), the highest rates of abnormal spermatozoa (35.83±4.4) and the highest concentrations of MDA in serum and seminal plasma compared to the control and other experimental groups.
Conclusion: The silver nanoparticles as a factor which increase the effects of free radicals and reactive oxygen species in serum and seminal fluid caused reduction of sperm parameters.